The present invention relates to an optical device, such as a magnification viewer, that is adapted to be supported on a wearer and allows the wearer to observe an object through a lens unit thereof.
Magnification viewers are used, for example, in surgeries, such as neurosurgery operation, which treat fine tissues and requires three dimensional magnification of the tissues that are difficult to distinguish with naked eyes.
FIG. 1 schematically shows a surgeon S having a conventional magnification viewer 100 on his head, sitting on a chair and carrying out a surgical operation. The magnification viewer 100 typically comprises a pair of spectacles 101 and a pair of magnifying lens systems 102 each of which being fixed to respective eyeglasses.
FIG. 2 is a cross sectional view of one of the eyeglasses 103 of the spectacles 101 and the magnifying lens system 102 fixed thereto.
The magnifying lens system 102 has a positive objective lens 102a and a negative ocular 102b which are housed within a lens barrel 102c to constitute a Galilean telescope.
The eyeglass 103 is provided with a hole 103a formed at a location lower than the center thereof. The magnifying lens system 102 is fixed to the eyeglass 103 in front of the hole 103a such that the optical axis of the magnifying lens system 102 inclines downwardly against the optical axis of the eyeglass 103.
FIGS. 3A and 3B schematically show side views of the surgeon observing an object with the conventional magnification viewer 100. In particular, FIG. 3A shows the surgeon observing a magnified image of the object through the magnifying lens system 102, and FIG. 3B shows the surgeon observing a normal image of the object through a portion of the eyeglass 103 above the magnifying lens system 102.
When the magnified image of the object is to be observed, the surgeon directs his/her face slightly downwards and turns his/her eyes considerably down, for example, for an angle of about 37 degrees, so that the object can be observed through the magnifying lens units. However, turning down the eyes for such a large angle causes much stress to the eyes and therefore the surgeon often complains extreme fatigue of the eyes.
When the normal image of the object is to be observed, the surgeon have to further incline the head downwards, for example, for an angle of 17 degrees as shown in FIG. 3B, to see the object through the upper part of the eyeglass 103 where the magnifying lens system 102 is not fixed. Such inclining of the head causes a significant fatigue at the neck, and if the surgeon have to keep the head inclined, or the neck bent, for a long time period, which may often happen in surgical operations, the neck may even be damaged.
It should be noted that the problems of the conventional magnification viewer described above in surgical operation also happens when utilized on a building site, in a underground mining or by restoration of paintings on a ceiling for observing objects above the head by inclining the head upwards.
Therefore, there was a need for a magnification viewer in which it is not required to extremely turn the eyes or incline the head for observing an object which is below or above the head.
The present invention is advantageous in that it provides an optical device that allows the observation of an object therethorugh which is not at the level of a head without considerably turning eyes or inclining the head.
According to an aspect of the invention, there is provided an optical device for observing an object therethrough. The optical device has a frame and at least one lens unit. The frame is adapted to be supported on a wearer. The lens unit is coupled to the frame so as to allow the wearer to observe an object therethrough. The lens unit includes a deflector that deflects a view direction of the wearer looking into the lens unit. Accordingly, the wearer can observe an object not at the same level of the head through the lens unit without considerably turning the eyes or inclining the head considerably.
Optionally, the lens unit provides a magnified image of the object so that the optical device can be utilized, for example, as a magnification viewer.
Further optionally, the optical device further includes at least one eyeglass that is held by the frame, and the lens unit is fixed to a portion of the eyeglass so that the wearer can observe an image not magnified by the lens unit through an other portion of the eyeglass.
Further optionally, the lens unit is fixed to the eyeglass such that the wearer can observe the object through the other portion of the eyeglass without inclining the head. For example, the lens unit is fixed the eyeglass at a location displaced from an optical axis of the eyeglass in a direction opposite to a direction in which the view direction of the wearer looking into the lens unit is deflected by said deflector. Such magnification viewer allows the wearer to alternately observe the magnified image and the normal image of the object by only turning the eyes.
Optionally, the optical device further includes a reflecting system which is disposed in front of the eyeglass, The reflecting system is disposed such that it bends a sight line of the wearer, looking through the other portion of the eyeglass, towards the object.
The reflecting system includes, for example, a half mirror, which is disposed on the optical axis of the magnifying lens unit between the object and the lens unit, and a mirror, which is disposed in front of the eyeglass on the sight line of the wearer looking through the other portion of the eyeglass. The half mirror reflects a part of the light coming from the object along the optical axis of the magnifying lens unit, and the mirror reflects the light from the half mirror towards the eye of the wearer. Accordingly, the wearer can observe the normal image of the object, or the image of the object not magnified by the magnifying lens unit, through the eyeglass without inclining the head.
Optionally, the lens unit includes an ocular and an objective lens constituting together a Galilean telescope, and the deflector, which may be a prism, is disposed between said ocular and said objective lens. The deflector is arranged such that it deflects the optical axis of the lens unit such that the image of the object observed therethrough is not inverted.
According to another aspect of the invention, a magnifying lens unit to be mounted to a pair of spectacles is provided. The magnifying unit includes an ocular having a first optical axis, a deflector disposed in front of the ocular and deflecting the first optical axis, and an objective lens having a second optical axis and disposed such that the second optical axis coincides with the first optical axis deflected by the deflector.
The magnifying lens unit arranged as above, allows one looking thereinto to observe an object that is not in a direction of the first optical axis without turning the eyes or head directly towards the object.
According to another object of the invention, a magnification viewer for observing an object therethrough is provided. The magnification viewer includes a pair of spectacles that has a frame and a pair of eyeglasses mounted to said frame, and a pair of magnification lens units each including an ocular and an objective lens. Each of the magnifying lens units is mounted to respective one of the eyeglasses. Each of the magnifying lens units includes a deflector for deflecting an optical axis of the magnifying lens unit so that the optical axis at the ocular inclines against the optical axis at the objective lens. The magnification viewer arranged as above deflects the view direction of a user looking into the magnifying lens unit and allows the user to observe an object without turning the eyes or inclining the head in order to direct the sight line toward it.